TOC a requirement for Kindle/MOBI - how to generate with asciidoctor-epub3 ?

This is from the "Amazon Kindle Publishing Guidelines":

"Amazon requires that all Kindle books include a logical TOC. The logical TOC is very important for a good
reading experience, because it allows a reader to navigate between chapters easily. Users expect to see
an HTML TOC when paging through a book from the beginning, while the logical TOC is an additional
way for users to navigate books. The inclusion of a logical TOC is especially important for books that are
longer than 20 pages."

However, unlike the PDF format of my book generated with asciidoctor-pdf, the EPUB and Kindle (MOBI) versions of my book generated with asciidoctor-epub3, ebook formats don't have a TOC whereas the PDF version does.

How can I generate a TOC using asciidoctor-epub3 ?

(Incidentally, without a TOC -- but having a NCX, which is generated and incorporated into the ebook -- when you list your book on Amazon, then "Look Inside" lists just "Cover" and "Beginning ...", not "Cover" and "Table of Contents" (plus entries in the TOC) as I do see for other books.)